Silicon-based composite negative electrode material, preparation method thereof and lithium-ion battery

A technology of negative electrode materials and composite materials, which is applied in the field of lithium ion batteries, silicon-based composite negative electrode materials and their preparation, can solve the problems of poor specific capacity and cycle performance of composite negative electrode materials, etc., and achieves significant conjugation effect and rapid improvement. The effect of charging performance and cycle life, high strength

Pending Publication Date: 2020-09-15
BTR NEW MATERIAL GRP CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Although this scheme has obtained a silicon-carbon composite negative electrode material, the specific capacity of the composite negative electrode material obtained by this scheme is poor, and the cycle performance also needs to be improved.

Method used

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  • Silicon-based composite negative electrode material, preparation method thereof and lithium-ion battery
  • Silicon-based composite negative electrode material, preparation method thereof and lithium-ion battery
  • Silicon-based composite negative electrode material, preparation method thereof and lithium-ion battery

Examples

Experimental program
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Effect test

Embodiment 1

[0108] This embodiment prepares the silicon-based composite negative electrode material according to the following method:

[0109] (1) Add 37.5g of natural graphite with a median diameter of 3μm, 4g of sodium dodecylbenzenesulfonate, and 20mL of ethanol into 200mL of water, accelerate stirring, and then add 60g of silicon particles with a median diameter of 50nm to the above liquid , spray drying after ultrasonication for 10 minutes to obtain the first composite material with a median particle size of 5 μm;

[0110] (2) The first composite material and epoxy resin (median particle size is 3 μm) are respectively added to the VC mixer according to the mass ratio of 1:0.8, mixed at a speed of 3000rpm / min for 1h, and then the mixture is placed in a high-temperature furnace , nitrogen gas was introduced, the temperature was raised to 1100°C at 2.0°C / min, kept for 5h, and cooled to room temperature naturally. The high-temperature product was pulverized and sieved to obtain a secon...

Embodiment 2

[0117] In this embodiment, except that the graphite used in step (1) is artificial graphite with a median particle size of 3 μm, other raw material types and operating conditions are the same as in Embodiment 1.

[0118] The silicon-based composite negative electrode material provided in this embodiment comprises an inner core and an outer shell positioned on the inner core surface, the inner core includes emulsified graphite and nano-silicon, the outer shell is composed of an inner layer positioned on the inner core surface and an outer layer positioned on the inner layer surface, the inner layer The layer is an amorphous carbon layer, and the outer layer is a polypyrrole-carbon nanotube composite material. The median particle size of artificial graphite is 3 μm, the median particle size of nano-silicon is 50 nm; the diameter of carbon nanotubes is 5 nm, and the length is 10 μm. Carbon nanotubes have sulfonic acid groups.

[0119] The silicon-based composite anode material p...

Embodiment 3

[0121] This embodiment prepares the silicon-based composite negative electrode material according to the following method:

[0122] (1) Add 37.5g of natural graphite with a median diameter of 2μm, 5g of fatty acid polyoxyethylene ester, and 20mL of ethanol into 200mL of water, accelerate stirring, then add 60g of silicon particles with a median diameter of 20nm to the above liquid, and ultrasonically Spray drying after 10 minutes to obtain the first composite material with a median particle size of 3.5 μm;

[0123] (2) The first composite material and epoxy resin (median particle size is 0.5 μm) are respectively added to the VC mixer according to the mass ratio of 1:0.8, mixed at 500rpm / min for 1.5h, and then the mixture is placed in In the high-temperature furnace, argon gas was introduced, the temperature was raised to 550°C at 1.0°C / min, kept for 8 hours, and naturally cooled to room temperature. The high-temperature product was pulverized and sieved to obtain a second com...

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Abstract

The invention provides a silicon-based composite negative electrode material, a preparation method thereof and a lithium-ion battery. The negative electrode material comprises an inner core and a shell located on the surface of the inner core, the inner core comprises emulsified graphite and nanometer silicon, and the shell comprises a carbon coating layer and a polymer-carbon nanometer material composite material. The preparation method comprises the following steps: mixing graphite, an emulsifier and a first solvent to obtain an emulsified graphite emulsion; mixing the emulsified graphite emulsion with nano-silicon, and granulating to obtain a first composite material; carrying out carbon coating on the first composite material to obtain a second composite material; and mixing the secondcomposite material, a carbon nanomaterial, a polymer monomer and a dopant in a second solvent, adding an oxidant for reaction, and performing solid-liquid separation to obtain the silicon-based composite negative electrode material. The silicon-based composite negative electrode material provided by the invention has relatively high reversible capacity and first coulombic efficiency, and has relatively low volume expansion and excellent cycle performance and rate capability.

Description

technical field [0001] The invention belongs to the technical field of energy storage materials, and relates to a negative electrode material, a preparation method thereof, and a lithium ion battery, in particular to a silicon-based composite negative electrode material, a preparation method thereof, and a lithium ion battery. Background technique [0002] The energy crisis and environmental problems are becoming increasingly prominent in today's society, and new clean energy and energy storage have become a hot research topic. In this context, lithium-ion batteries have basically occupied the market of portable consumer electronics due to their high energy density, high power density, long life and environmental friendliness, and are widely used in electric vehicles, large-scale energy storage equipment, decentralized Mobile power and other fields have broad application prospects. However, with the growth of people's demand, especially in the booming field of electric vehi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/38H01M4/583H01M4/62H01M10/0525B82Y30/00
CPCH01M4/366H01M4/386H01M4/583H01M4/625H01M10/0525B82Y30/00H01M2004/027Y02E60/10
Inventor 何鹏苏航李晓栋任建国贺雪琴李阳兴
Owner BTR NEW MATERIAL GRP CO LTD
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